The invention relates to a unit for a flow-ducting system with a combined pump-drive module, the pump-drive module comprising a drive module, and a pump module having an impeller that can be driven by said drive module, the unit comprising a casing having at least one inlet side and at least one outlet side and a moveable shut-off device arranged between them, a flow path between the inlet side and the outlet side being formed in at least one position of the shut-off device, and the pump module being arranged in the flow path between the inlet side and the outlet side.
PCT patent publication no. WO 2009/070565 discloses a unit of the foregoing general type. A flow-ducting unit constructed as pump comprises a casing having at least one inlet and at least one outlet. An impeller for delivering a fluid is driven by a motor. A rotatable valve is arranged between the impeller and the outlet side of the pump and has an aperture. The valve serves, by means of the rotatably positioned aperture, to channel a fluid flow into various outlets or outlet ducts. The flow-ducting unit of WO 2009/070565 has an elaborate construction and has the further disadvantage that the flow path has to be separated when servicing the pump. Such a construction therefore cannot be used for many applications, for example in chemical engineering.
U.S. Pat. No. 6,619,935 (=WO 01/07836) discloses a mixing valve having a casing with inlets and outlets on the casing, and controlling the connection between the inlets and outlets a control element, which is embodied as a rotating pump impeller, which through axial displacement controls the connection between the inlets and outlets lying in different planes. The pump impeller is driven by a motor via a hollow shaft. In this mixing valve with integral pump various flow paths can be achieved as a function of the axially displaceable control element. In this construction, used especially for mixing valves in closed heating circuits, the pump impeller is an integral part of the control element. When servicing, the entire arrangement has to be removed, giving rise to the disadvantages described above.
German patent application publication no. DE 1 912 655 A discloses a three-way mixing valve combined with a pump. In a valve casing, dividing walls separate three chambers, of which a middle chamber is embodied as pump chamber having a valve outlet, and the other two chambers are each connected to a valve inlet. A hollow cylindrical centrifugal pump body, coupled to a drive motor and rotatably supported in the dividing walls, is arranged in the middle chamber. This body is connected to the other two chambers and the passage cross section of its admission apertures can be regulated by two externally actuated valve bodies seated on a common valve stem. Any adjustment of the valve stem between two limit positions of the valve bodies is catered for. The pump module here always remains connected to the valve outlet.